In the event of traumatic injury, e.g. in an automobile accident, a major fall or the like, the injured individual must be given immediate medical treatment and for this purpose, hospitals or similar institutions have established emergency rooms, trauma centers, or other immediate care facilities. For transportation from the scene of the accident to such facility, it is now routine practice for the patient to be arranged at the scene on what is known as a trauma or spine board. These boards are flat or planar for easy storage in a minimum of space, of generally rectangular shape with a length of seven feet or so, and are provided with handholes at spaced intervals along their side margins for carrying. A shortened version, intended mainly for torso support only, is illustrated in U.S. Pat. No. 4,127,120. Currently available trauma boards are equipped with restraining devices such as adjustable chest or torso straps, which usually criss-cross over the patient's chest or torso, being connected to the boards at the four opposite corners of the torso, and head immobilizer blocks to prevent as much as possible any movement of the head and neck by the patient and thus minimize the possibility of aggravation of any existing injuries. In addition, a cervical collar is usually placed on the patient for direct cervical support for the same reason.
Because of the likelihood of damage to the cervical spine due to whiplash and similar impact reaction, the trauma patient upon arrival at the trauma treatment facility is naturally under suspicion of cervical spine injury and one of the first concerns of the attending personnel, after administering immediate life-saying treatment, is to investigate whether such injury is in fact present. This requires the exposure by lateral projection, i.e. from a position to one side of the cervical region of the patient, of an X-ray or other radiographic photograph of the complete cervical section of the spine, including all seven bones of that region. This exposure must take place while the patient remains fully immobilized on the trauma board with a minimum of physical disturbance of the relative position on the board.
As is well recognized in the art, for example, U.S. Pat. Nos. 3,629,581, 4,383,524, 4,669,106, and 4,674,483, diagnostic radiography by lateral projection of the full cervical spine on a supine patient is troublesome. The natural position of the shoulders of a patient in that position is in lateral alignment with the sixth and seventh vertebrae of the cervical region which obstructs a clear view of those vertebrae. Prior attempts to overcome this problem have not proved entirely satisfactory from the standpoint of the trauma professional.
The traditional technique, that is still frequently employed today, is for an attendant to stand at the foot of the patient anchored on the trauma board resting on a gurney cart facing toward the patient's head, bend from the waist as necessary to grasp a hand or wrist of the patient in each hand, and pull firmly toward the feet until the shoulder girdle is displaced angularly out of lateral coincidence with the sixth and seventh vertebrae. However, it is difficult for the attendant in this bent-over position to judge the correct degree of the force to be applied to the patient's arms with the risk that such force is either insufficient or in excess of what is needed. Moreover, the attendant is at risk of exposure to stray X-ray radiation since effective shielding under the circumstances is virtually impossible.
One early visualization appliance disclosed in U.S. Pat. No. 3,629,581 sought to avoid this problem by resort to mechanical advantage in the form of a double-acting windlass mounted on the outer face of the footboard against the opposite face of which the feet of the patient are pressed. Wrist straps having an adjustable loop at one end for engaging the patient's wrists are connected at their other end to the windlass. Rotation of the handle of the windlass winds the straps equally, drawing the patient's arms and shoulder girdle footwardly. Reverse rotation is prevented by a pawl engaging teeth on a pinion rotating with the windlass until the pawl is released.
But the mechanical advantage can prove to be a disadvantage because it precludes any direct sense by the operator of the magnitude of the applied force and introduces the possibility of excessive traction being applied with consequential injury. Moreover, satisfactory operation of this arrangement is necessarily dependent upon a state of rigidity for the patient's legs to resist the applied tractive force. Unless the patient is conscious and cooperative, which is often not the case, or the legs are restrained by straps or by pressure exerted manually by the attendant, the knees will tend to flex when subjected to significant axial compressive force and defeat the desired result. Finally, this approach is absolutely contra-indicated where there is injury to the leg and pelvic region, as can easily be present in trauma patients.
A generally similar but simplified suggestion appears in U.S. Pat. No. 4,383,524 using an inextensible strap which is attached to the wrists by wrist bands at its ends, or, alternatively, directly to the shoulders via shoulder slings, and passed as a U-shaped loop of adjustable length beneath the patient's feet. Separate straps for each wrist can be used instead of a single strap with the free ends being joined together beneath the feet by hook-and-loop fasteners, such as are sold under the tradename "VELCRO". Initially, after the wrist bands are in place, the patient's knees are flexed slightly while the U-shaped loop of the strap is pulled tight against the patient's feet. Then the knees are straightened so as to tension the U-shaped loop and apply traction to the arms and thence to the shoulders and thereby retract the shoulders in a distal direction clear of the lower cervical spine.
Obviously, the degree to which the knees are flexed at the beginning determines the degree of shoulder retraction and gauging the correct degree is more often than not a matter of trial and error which is awkward and time-consuming. Nor can one effectively circumvent this problem by deliberately selecting too much flexure with the expectation that the patient can compensate by maintaining the legs in a suitable intermediate position. But without the knees being locked in straight position, it is difficult for the patient to exert in stable fashion the considerable amount of force required for sufficient shoulder retraction. At the other extreme, too little flexure results immediately in inadequate retraction.
As with the earlier system, the intervention of the legs in maintaining tractive tension requires a conscious and cooperative patient or the assistance of an attendant and in any case disqualifies patients with injuries to their lower extremities.
Another system utilizing mechanical advantage but in a far more complicated arrangement is found in U.S. Pat. No. 4,669,106 wherein mechanical pressure is applied directly against the tops of the shoulders in a footward direction while bodily movement in the same direction is prevented. To this end, shoulder-contacting abutments are mounted adjustably on a pressure plate slidably supported at the upper end of a trauma board and a mechanical winch is operated to mechanically drive the plate distally and thus apply sufficient pressure via the abutments directly against the shoulder surfaces to cause their retraction. To keep the body from sliding axially under this pressure, a pontel-like post is fixed to an adjustable median point of the board for engagement by the crotch or perineal region of the patient.
Both the abutment-carrying pressure plate and the crotch pontel must be already in position on the board in advance of placement of the patient thereon so that every trauma board would require rather expensive modification for the practice of this invention. Also, given the significant level of traction force required for shoulder retraction, the application to the crotch region of resistance sufficient to withstand such force would be uncomfortable if not downright painful and would be totally unacceptable if injuries to the pelvic region e.g. a pelvic fracture, were present. Finally, if, as is usual, a cervical collar has been affixed to the patient, it would interfere with the proper positioning of the abutments against the tops of the shoulders.
A shoulder retraction appliance specifically configured for cooperation with computerized axial tomography (CAT) scanning units is shown in U.S. Pat. No. 4,674,483. Such units have a channel-like axial recess in which the patient rests and the appliance consists of a concavely curved baseboard resting within the recess and supporting an upstanding footboard buttressed from below to form a rigid assembly extending partially beneath the patient's legs with the feet planted against the footboard. A shoulder sling encircles each shoulder and is connected to a tether which extends to the footboard and is anchored after sufficient tensioning to the top of the latter by a wedge-type cleat.
In practice, shoulder slings perform poorly because of the difficulty in preventing such slings from slipping free of the shoulders, particularly since movement of the shoulders under traction to a distally retracted position increases the slope angle of the shoulders from the neck to the axilla. This inherently promotes sliding disengagement of the slings which naturally follow the path of least resistance. Further, if a cervical collar and/or head restraining blocks are in position, attachment of shoulder slings becomes almost impossible unless the straps and blocks are first removed, making possible movement of the patient, who may not be in a mentally competent state at the time, and increasing the danger of cervical complications.
The use of a curved baseboard while ideal for CAT scan units is undesirable for association with present day trauma boards which are flat for storage in the cramped quarters of an EMS vehicle since the curved baseboard will be unstable and subject to rocking movement if placed either on or below an end of a trauma board. Likewise, wedge-type cleats for gripping the free ends of the shoulder sling tethers permit release of the tether ends only when additional tension is applied to the tethers. If the operative tension for satisfactory shoulder retraction has already approached the maximum desirable level, this added tension for release of the tethers could have adverse effects on the nerves, muscles, and joints of the shoulders of the patient.
Although visualization of all seven of the cervical vertebrae in a single X-ray radiograph is ideal for diagnostic purposes, this is not always possible. There are physical conditions which preclude this ideal result even under the best of circumstances and equipment, such as patients with a seventh cervical rib or with such developed shoulder muscularity that maximum retraction fails to eliminate the obstruction of the seventh cervical vertebrae in lateral projection. For these special cases, a variation known as the "swimmer's" or Twining position has been developed. To achieve this position, one shoulder is retracted distally while the opposite arm is raised above the head with the elbow bent at right angles and the forearm is adducted over the head. With the patient in this position, an X-ray beam is able to pass through an area centered on the seventh cervical vertebrae free of superimposition of the shoulders. The resultant image while inferior diagnostically to a true lateral radiograph of the full cervical spine, is sufficient useful to rule out, or identify, as the case may be, a fracture, dislocation, or subluxation of the sixth and seventh cervical vertebrae. It is critical to the successful resort to this variant position that one is able to raise one shoulder while elevating the other to an extent permitting visualization of the area of interest.
Visualization appliances that cannot accommodate the "swimmer's" or Twining position, such as U.S. Pat. No. 4,669,106, have limited utility and are less desirable to a "full-service" trauma facility.
There is thus a need in the field of trauma medicine for an appliance for assisting the radiographic visualization in lateral projection of the complete cervical spine that is free of the various disadvantages and drawbacks of the devices that have so far been proposed for this purpose.